/*
 * crypto_kernel.c
 *
 * header for the cryptographic kernel
 *
 * David A. McGrew
 * Cisco Systems, Inc.
 */
/*
 *
 * Copyright(c) 2001-2006 Cisco Systems, Inc.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *   Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 *
 *   Redistributions in binary form must reproduce the above
 *   copyright notice, this list of conditions and the following
 *   disclaimer in the documentation and/or other materials provided
 *   with the distribution.
 *
 *   Neither the name of the Cisco Systems, Inc. nor the names of its
 *   contributors may be used to endorse or promote products derived
 *   from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
 * INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
 * (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
 * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED
 * OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "alloc.h"

#include "crypto_kernel.h"

/* the debug module for the crypto_kernel */

debug_module_t mod_crypto_kernel = { 0, /* debugging is off by default */
"crypto kernel" /* printable name for module   */
};

/*
 * other debug modules that can be included in the kernel
 */

extern debug_module_t mod_auth;
extern debug_module_t mod_cipher;
extern debug_module_t mod_stat;
extern debug_module_t mod_alloc;

/*
 * cipher types that can be included in the kernel
 */

extern cipher_type_t null_cipher;
extern cipher_type_t aes_icm;
extern cipher_type_t aes_cbc;

/*
 * auth func types that can be included in the kernel
 */

extern auth_type_t null_auth;
extern auth_type_t hmac;

/* crypto_kernel is a global variable, the only one of its datatype */

crypto_kernel_t crypto_kernel = { crypto_kernel_state_insecure, /* start off in insecure state */
NULL, /* no cipher types yet         */
NULL, /* no auth types yet           */
NULL /* no debug modules yet        */
};

#define MAX_RNG_TRIALS 25

// The only reason to have this forceInit argument, is to make sure
// we properly initialize ourselves to run dtls_asrtpa_driver test.
// In past, dtls_asrtpa_driver was running as a separate process
// (actually, all srtp tests were running as individual processes).
// Now, they all run inside a single process, so we must make sure
// we reset the state (if necessary) in between test runs.
err_status_t crypto_kernel_init(int forceInit) {
    err_status_t status;

    if (forceInit) {
        memset(&crypto_kernel, 0, sizeof(crypto_kernel));
    }

    /* check the security state */
    if (crypto_kernel.state == crypto_kernel_state_secure) {

        /*
         * we're already in the secure state, but we've been asked to
         * re-initialize, so we just re-run the self-tests and then return
         */
        return crypto_kernel_status();
    }

    /* load debug modules */
    status = crypto_kernel_load_debug_module(&mod_crypto_kernel);
    if (status)
        return status;
    status = crypto_kernel_load_debug_module(&mod_auth);
    if (status)
        return status;
    status = crypto_kernel_load_debug_module(&mod_cipher);
    if (status)
        return status;
    status = crypto_kernel_load_debug_module(&mod_stat);
    if (status)
        return status;
    status = crypto_kernel_load_debug_module(&mod_alloc);
    if (status)
        return status;

    /* initialize random number generator */
    status = rand_source_init();
    if (status)
        return status;

    /* run FIPS-140 statistical tests on rand_source */
    status = stat_test_rand_source_with_repetition(
            rand_source_get_octet_string, MAX_RNG_TRIALS);
    if (status)
        return status;

    /* initialize pseudorandom number generator */
    status = ctr_prng_init(rand_source_get_octet_string);
    if (status)
        return status;

    /* run FIPS-140 statistical tests on ctr_prng */
    status = stat_test_rand_source_with_repetition(ctr_prng_get_octet_string,
            MAX_RNG_TRIALS);
    if (status)
        return status;

    /* load cipher types */
    status = crypto_kernel_load_cipher_type(&null_cipher, NULL_CIPHER);
    if (status)
        return status;
    status = crypto_kernel_load_cipher_type(&aes_icm, AES_128_ICM);
    if (status)
        return status;
    status = crypto_kernel_load_cipher_type(&aes_cbc, AES_128_CBC);
    if (status)
        return status;

    /* load auth func types */
    status = crypto_kernel_load_auth_type(&null_auth, NULL_AUTH);
    if (status)
        return status;
    status = crypto_kernel_load_auth_type(&hmac, HMAC_SHA1);
    if (status)
        return status;

    /* change state to secure */
    crypto_kernel.state = crypto_kernel_state_secure;

    return err_status_ok;
}

err_status_t crypto_kernel_status() {
    err_status_t status;
    kernel_cipher_type_t *ctype = crypto_kernel.cipher_type_list;
    kernel_auth_type_t *atype = crypto_kernel.auth_type_list;
    kernel_debug_module_t *dm = crypto_kernel.debug_module_list;

    /* run FIPS-140 statistical tests on rand_source */
    printf("testing rand_source...");
    status = stat_test_rand_source_with_repetition(
            rand_source_get_octet_string, MAX_RNG_TRIALS);
    if (status) {
        printf("failed\n");
        crypto_kernel.state = crypto_kernel_state_insecure;
        return status;
    }
    printf("passed\n");

    /* for each cipher type, describe and test */
    while (ctype != NULL) {
        printf("cipher: %s\n", ctype->cipher_type->description);
        printf("  instance count: %d\n", ctype->cipher_type->ref_count);
        printf("  self-test: ");
        status = cipher_type_self_test(ctype->cipher_type);
        if (status) {
            printf("failed with error code %d\n", status);
            exit(status);
        }
        printf("passed\n");
        ctype = ctype->next;
    }

    /* for each auth type, describe and test */
    while (atype != NULL) {
        printf("auth func: %s\n", atype->auth_type->description);
        printf("  instance count: %d\n", atype->auth_type->ref_count);
        printf("  self-test: ");
        status = auth_type_self_test(atype->auth_type);
        if (status) {
            printf("failed with error code %d\n", status);
            exit(status);
        }
        printf("passed\n");
        atype = atype->next;
    }

    /* describe each debug module */
    printf("debug modules loaded:\n");
    while (dm != NULL) {
        printf("  %s ", dm->mod->name);
        if (dm->mod->on)
            printf("(on)\n");
        else
            printf("(off)\n");
        dm = dm->next;
    }

    return err_status_ok;
}

err_status_t crypto_kernel_list_debug_modules() {
    kernel_debug_module_t *dm = crypto_kernel.debug_module_list;

    /* describe each debug module */
    printf("debug modules loaded:\n");
    while (dm != NULL) {
        printf("  %s ", dm->mod->name);
        if (dm->mod->on)
            printf("(on)\n");
        else
            printf("(off)\n");
        dm = dm->next;
    }

    return err_status_ok;
}

err_status_t crypto_kernel_shutdown() {
    err_status_t status;

    /*
     * free dynamic memory used in crypto_kernel at present
     */

    /* walk down cipher type list, freeing memory */
    while (crypto_kernel.cipher_type_list != NULL) {
        kernel_cipher_type_t *ctype = crypto_kernel.cipher_type_list;
        crypto_kernel.cipher_type_list = ctype->next;
        debug_print(mod_crypto_kernel, "freeing memory for cipher %s",
                ctype->cipher_type->description);
        crypto_free(ctype);
    }

    /* walk down authetication module list, freeing memory */
    while (crypto_kernel.auth_type_list != NULL) {
        kernel_auth_type_t *atype = crypto_kernel.auth_type_list;
        crypto_kernel.auth_type_list = atype->next;
        debug_print(mod_crypto_kernel, "freeing memory for authentication %s",
                atype->auth_type->description);
        crypto_free(atype);
    }

    /* walk down debug module list, freeing memory */
    while (crypto_kernel.debug_module_list != NULL) {
        kernel_debug_module_t *kdm = crypto_kernel.debug_module_list;
        crypto_kernel.debug_module_list = kdm->next;
        debug_print(mod_crypto_kernel, "freeing memory for debug module %s",
                kdm->mod->name);
        crypto_free(kdm);
    }

    /* de-initialize random number generator */
    status = rand_source_deinit();
    if (status)
        return status;

    /* return to insecure state */
    crypto_kernel.state = crypto_kernel_state_insecure;

    return err_status_ok;
}

err_status_t crypto_kernel_load_cipher_type(cipher_type_t *new_ct,
        cipher_type_id_t id) {
    kernel_cipher_type_t *ctype, *new_ctype;
    err_status_t status;

    /* defensive coding */
    if (new_ct == NULL)
        return err_status_bad_param;

    /* check cipher type by running self-test */
    status = cipher_type_self_test(new_ct);
    if (status) {
        return status;
    }

    /* walk down list, checking if this type is in the list already  */
    ctype = crypto_kernel.cipher_type_list;
    while (ctype != NULL) {
        if ((new_ct == ctype->cipher_type) || (id == ctype->id))
            return err_status_bad_param;
        ctype = ctype->next;
    }

    /* put new_ct at the head of the list */
    /* allocate memory */
    new_ctype = (kernel_cipher_type_t *) crypto_alloc(
            sizeof(kernel_cipher_type_t));
    if (new_ctype == NULL)
        return err_status_alloc_fail;

    /* set fields */
    new_ctype->cipher_type = new_ct;
    new_ctype->id = id;
    new_ctype->next = crypto_kernel.cipher_type_list;

    /* set head of list to new cipher type */
    crypto_kernel.cipher_type_list = new_ctype;

    /* load debug module, if there is one present */
    if (new_ct->debug != NULL)
        crypto_kernel_load_debug_module(new_ct->debug);
    /* we could check for errors here */

    return err_status_ok;
}

err_status_t crypto_kernel_load_auth_type(auth_type_t *new_at,
        auth_type_id_t id) {
    kernel_auth_type_t *atype, *new_atype;
    err_status_t status;

    /* defensive coding */
    if (new_at == NULL)
        return err_status_bad_param;

    /* check auth type by running self-test */
    status = auth_type_self_test(new_at);
    if (status) {
        return status;
    }

    /* walk down list, checking if this type is in the list already  */
    atype = crypto_kernel.auth_type_list;
    while (atype != NULL) {
        if ((new_at == atype->auth_type) || (id == atype->id))
            return err_status_bad_param;
        atype = atype->next;
    }

    /* put new_at at the head of the list */
    /* allocate memory */
    new_atype = (kernel_auth_type_t *) crypto_alloc(sizeof(kernel_auth_type_t));
    if (new_atype == NULL)
        return err_status_alloc_fail;

    /* set fields */
    new_atype->auth_type = new_at;
    new_atype->id = id;
    new_atype->next = crypto_kernel.auth_type_list;

    /* set head of list to new auth type */
    crypto_kernel.auth_type_list = new_atype;

    /* load debug module, if there is one present */
    if (new_at->debug != NULL)
        crypto_kernel_load_debug_module(new_at->debug);
    /* we could check for errors here */

    return err_status_ok;

}

cipher_type_t *
crypto_kernel_get_cipher_type(cipher_type_id_t id) {
    kernel_cipher_type_t *ctype;

    /* walk down list, looking for id  */
    ctype = crypto_kernel.cipher_type_list;
    while (ctype != NULL) {
        if (id == ctype->id)
            return ctype->cipher_type;
        ctype = ctype->next;
    }

    /* haven't found the right one, indicate failure by returning NULL */
    return NULL;
}

err_status_t crypto_kernel_alloc_cipher(cipher_type_id_t id,
        cipher_pointer_t *cp, int key_len) {
    cipher_type_t *ct;

    /*
     * if the crypto_kernel is not yet initialized, we refuse to allocate
     * any ciphers - this is a bit extra-paranoid
     */
    if (crypto_kernel.state != crypto_kernel_state_secure)
        return err_status_init_fail;

    ct = crypto_kernel_get_cipher_type(id);
    if (!ct)
        return err_status_fail;

    return ((ct)->alloc(cp, key_len));
}

auth_type_t *
crypto_kernel_get_auth_type(auth_type_id_t id) {
    kernel_auth_type_t *atype;

    /* walk down list, looking for id  */
    atype = crypto_kernel.auth_type_list;
    while (atype != NULL) {
        if (id == atype->id)
            return atype->auth_type;
        atype = atype->next;
    }

    /* haven't found the right one, indicate failure by returning NULL */
    return NULL;
}

err_status_t crypto_kernel_alloc_auth(auth_type_id_t id, auth_pointer_t *ap,
        int key_len, int tag_len) {
    auth_type_t *at;

    /*
     * if the crypto_kernel is not yet initialized, we refuse to allocate
     * any auth functions - this is a bit extra-paranoid
     */
    if (crypto_kernel.state != crypto_kernel_state_secure)
        return err_status_init_fail;

    at = crypto_kernel_get_auth_type(id);
    if (!at)
        return err_status_fail;

    return ((at)->alloc(ap, key_len, tag_len));
}

err_status_t crypto_kernel_load_debug_module(debug_module_t *new_dm) {
    kernel_debug_module_t *kdm, *new;

    /* defensive coding */
    if (new_dm == NULL)
        return err_status_bad_param;

    /* walk down list, checking if this type is in the list already  */
    kdm = crypto_kernel.debug_module_list;
    while (kdm != NULL) {
        if (strncmp(new_dm->name, kdm->mod->name, 64) == 0)
            return err_status_bad_param;
        kdm = kdm->next;
    }

    /* put new_dm at the head of the list */
    /* allocate memory */
    new = (kernel_debug_module_t *)crypto_alloc(sizeof(kernel_debug_module_t));
    if (new == NULL)
        return err_status_alloc_fail;

    /* set fields */
    new->mod = new_dm;
    new->next = crypto_kernel.debug_module_list;

    /* set head of list to new cipher type */
    crypto_kernel.debug_module_list = new;

    return err_status_ok;
}

err_status_t crypto_kernel_set_debug_module(char *name, int on) {
    kernel_debug_module_t *kdm;

    /* walk down list, checking if this type is in the list already  */
    kdm = crypto_kernel.debug_module_list;
    while (kdm != NULL) {
        if (strncmp(name, kdm->mod->name, 64) == 0) {
            kdm->mod->on = on;
            return err_status_ok;
        }
        kdm = kdm->next;
    }

    return err_status_fail;
}

err_status_t crypto_get_random(unsigned char *buffer, unsigned int length) {
    if (crypto_kernel.state == crypto_kernel_state_secure)
        return ctr_prng_get_octet_string(buffer, length);
    else
        return err_status_fail;
}
